Definition is a tool, not a solution.
If you can arrive at a definition that informs and explains and serves as a shorthand for useful meaning, it is great and useful.
If it only leads to further disagreement, it's not so helpful.
I'm not sure that "pornography" is something you can define, either inductively, or deductively, because in essence it is just an affront to values that we either hold, or think we should hold.
Abuse and mistreatment are things that we are more likely to agree on. Objectification and diminution of personal integrity are others that we can probably get somewhat close to agreeing on.
If you value keeping genitalia or female breasts private, or at least something that is only shared intimately, with those who you know, love and respect, than full nudity is an affront. If you consider genitalia or female breasts to be nothing more than an attractive part of the human anatomy, to be shared, or not, as circumstances dictate, then you will not consider full nudity an affront.
If you consider sexual activity as something that is best shared only in private, you will consider the public display of sexual activity an affront. If you are comfortable with the public display of sexual activity, and consider that to be appropriate, then you will not consider the public display of sexual activity an affront.
It is the imposition of others' values on these issues that causes problems. Further, it is the attempt by others, to impose their values on those who don't share them, that really causes problems.
IMHO we should welcome the arguments of those whose values we, at first instance, don't share. We may be convinced, if not in general, at least in the specific instance.
As far as I'm concerned, if someone says they are upset and offended by something that bothers them, I don't have any problem in respecting their desire not to be exposed to that something, and I'm happy to hear their arguments why I should be offended as well.
Don't get me wrong, I have preferences. Like a lot of males, I am much more comfortable with female nudity, than male nudity. I just think it important to both protect my sensibilities, while at the same time not attempting to impose my choices on others.
$0.02 worth, as usual.